In a more limited sense, the present invention has to do with a dry cleaning apparatus for use in such a cleaning process and with a cleaning plant for the dry cleaning of pieces of fabric as for example clothing, the apparatus having a processing space formed by a turning tumbler or tumbler drum which is joined up with a solvent circulation system and a hot air circulation system, whose operation takes place after that of the solvent circulation system, each such circulation system having a pump therein. Furthermore the solvent circulation system has a dirt filter, whereas the hot air circulation system has an air cooler with a condensate trap and an air heater coming after the air cooler in the direction motion of the air.
Such plant is known in the art. In such a plant or apparatus, the dirt washed out in the washing operation is kept back and taken up by the filter unit so that, dependent on the design of such unit, the filter unit has to be cleaned or the filter cartridge therein has to be taken out and a new one put in its place. In this case, in the prior art, for example in an apparatus having an "expander filter", the first step is to take out the filter cake produced, and to put it in a still vessel with the solvent from the solvent circulation system, the still forming part of a solvent processing and recovery unit so that the solvent may be recovered for further use. In the distillation process using the still, dyes and bacteria, for example, are cleared from the solvent.
However, the outcome of such processing is that the still or distillation apparatus becomes dirty so that work of disposing of the dirt is not made any simpler but only undertaken in a different part of the apparatus. In other cases in which throw-away filters, made for example of paper, are used, there are still troubles in connection with disposal of the used filter papers, inasfar as there will in all cases still be a certain amount of solvent in the dirt sticking to the filter paper so that, for safeguarding the environment, it is not possible for the filters simply to be thrown away and they have to be taken care of by special organizations as chemical waste, this being complex and expensive.